NEW DELHI, July 31 (Reuters) : US Commerce Secretary Penny Pritzker held out hope that differences with India over a deal on easing global trade would be resolved and an agreement would be reached by the end of a World Trade Organisation deadline on Thursday.

New Delhi has insisted that, in exchange for signing up to the trade facilitation agreement, it wants to see more progress on a parallel pact giving it more freedom to subsidise and stockpile food grains than is allowed under WTO rules.

“I am an optimist, I am hopeful that within the period of today...that there is a common ground that is found,” Pritzker, who is accompanying Secretary of State John Kerry for an annual strategic dialogue with Indian government leaders, told NDTV.

Earlier in the day, Kerry and Pritzker had raised the issue with finance minister Arun Jaitley, but Jaitley merely repeated his country’s position, a source at the meeting said.

According to the source, who declined to be identified, neither side put forward any suggestions on how to break the deadlock.

The deal must be signed in Geneva on Thursday, and India's ultimatum has revived doubts about the future of the WTO as a negotiating body.

Several diplomats said New Delhi's stance could derail the whole process of world trade liberalisation, leading some WTO nations to discuss informally a last-resort idea of excluding India from the agreement.

“If India does end up blocking (on Thursday) there is already a group of members who are interested in pursuing that path,” a source involved in the discussions said.

“A dozen or so” of the WTO's 160 members had informally discussed pushing ahead with the trade facilitation agreement with less than 100 per cent participation, the source said.

The WTO says a successful deal could add $1 trillion to the global economy and create 21 million jobs.

An Australian trade official with knowledge of the talks said a group of countries including the United States, European Union, Australia, Japan, Canada and Norway began discussing the possibility in Geneva on Wednesday afternoon.

A Japanese official familiar with the negotiations said Japan was still working on reaching a consensus, while a State Department official travelling with Kerry in India said the United States continued to talk with India on the deal.

A WTO spokesman said the group's director-general would hold meetings throughout the day to “avert a crisis.

“Delegations are showing real commitment to finding a solution and the director-general remains hopeful that a solution can be found,” he said.

US trade officials in Washington were not available for comment, given the late hour, while EU, Canadian and Norwegian officials could not immediately be reached for comment.

Technical details would still have to be ironed out, but there was a “credible core group” that would be ready to start talking about a deal without India when WTO diplomats return from their summer break, the Australian official said.